A wide variety of absorbent structures designed to be efficient for the absorption of body fluids such as blood, urine, menses, and the like, are known. Disposable products of this type generally comprise some sort of fluid-permeable topsheet material, an absorbent core, and a fluid-impermeable backsheet material.
Heretofore, such absorbent structures have been prepared using, for example, topsheet materials prepared from woven, nonwoven, or porous formed-film polyethylene or polypropylene materials. Backsheet materials typically comprise flexible polyethylene sheets. Absorbent core materials typically comprise wood pulp fibers or wood pulp fibers in combination with absorbent gelling materials.
One aspect of such sanitary products which has recently been considered is their disposability. Although such products largely comprise materials which would be expected ultimately to degrade, and although products of this type contribute only a very small percentage of the total solid waste materials generated by consumers each year, nevertheless there is currently a perceived need to devise such disposable products from materials which degrade relatively quickly, thereby lessening their bulk.
Various attempts have been made to provide modified polymeric backsheets which would be more degradable than backsheet materials currently in use. Alternatively, it might seem reasonable to use paper backsheets. However, most paper sheets have too little wet strength to be useful in articles such as diapers, and the like, which must function in the presence of large amounts of moisture. While some relatively water-stable papers are known, they are generally too stiff in their dry state to provide the quality of disposable articles the consumer has come to expect.
More particularly, the present invention employs a paper backsheet which is treated with a polycationic latex material, as described hereinafter, which substantially enhances the wet strength of said paper, but without undesirably enhancing its dry strength to the extent that the resulting article is unattractively stiff or "crinkly". Stated succinctly, the practice of the present invention employs a new type of treated paper as the backsheet for such disposable articles.